also affects neurons (NERVEcells) and the function-
ing of the CENTRAL NERVOUS SYSTEM, resulting in
behavioral disturbances, delusions, confusion, and
DEMENTIA. Disturbances of neuromuscular function
include rigidity and involuntary activation of
reflexes. The diagnostic path includes BLOODtests
to measure the levels of niacin and tryptophan in
the blood circulation. The diagnosis is primarily
clinical, however, based on the presenting symp-
toms and their response to treatment with niacin
supplementation.
Treatment Options and Outlook
Treatment is immediate supplementation with
niacin, usually in the form of niacinamide, and
correction of EATING HABITSto restore foods to the
diet that provide niacin. At therapeutic doses
niacin often causes uncomfortable symptoms such
as SKIN flushing and tingling; the niacinamide
form, a slightly different chemical structure, does
not. Both chemical forms provide the body with
the niacin the cells need for energy conversion.
Though many of pellagra’s symptoms are
reversible, those affecting the skin often result in
permanent changes that are sometimes disfigur-
ing. Untreated pellagra results in multisystem
organ failure that is usually fatal.
Risk Factors and Preventive Measures
Pellagra develops as a consequence of niacin defi-
ciency; thus adequate niacin intake prevents pella-
gra. Most people can obtain sufficient niacin
supplies through the foods they eat. Meats, poul-
try, and other animal-based proteins contain high
amounts of tryptophan, which the body converts
to niacinamide. Asparagus, mushrooms, potatoes,
spinach, peanuts and peanut butter, and legumes
contain high amounts of niacin.
People who eat large quantities of corn and
foods made with corn flour and who do not eat
other kinds of foods, are at high risk for pellagra.
The niacin in corn is not available through diges-
tion. Other people at high risk for pellagra are
those taking long-term treatment with isoniazid
for TUBERCULOSISor who have chronic CIRRHOSIS
(the LIVER is fundamental in converting trypto-
phan to niacinamide).
See also ANEMIA; BERIBERI; DELUSION; NEURON;
NUTRITIONAL DEFICIENCY; NUTRITIONAL NEEDS; RICKETS;
SCURVY; VITAMINS AND HEALTH.rickets A health condition that results from
long-term deficiency of vitamin D, also called cal-
ciferol or ergocalciferol, in which the bones can-
not absorb calcium or build new BONEtissue. The
body makes most of the vitamin D it requires from
cholesterol and sunlight. Dietary sources of vita-
min D are primarily those that contain added sup-
plements such as dairy products, orange juice, and
some SOY-based food products. Cod liver oil natu-
rally contains ergosterol, a form of vitamin D
called D 2 , as do oily fish such as salmon and sar-
dines (though not in as high a concentration as
cod liver oil). Supplemental vitamin D also inter-
acts with cholesterol to form calcitriol.
The LIVERmanufactures cholesterol, the base for
vitamin D, and sends a certain amount for stor-
age in the cells of the SKIN. Exposure to the sun’s
ultraviolet B (UVB) rays activates a series of
chemical changes that convert the stored choles-
terol molecules to a HORMONEform of vitamin D
called calcitriol. The liver and the KIDNEYSalso par-rickets 199PELLAGRA SYMPTOMSGastrointestinal Dermatologic Neurologic
DIARRHEA bullae (blisters) anxiety
GASTROINTESTINAL BLEEDING erythema DEMENTIA
GLOSSITIS hyperpigmentation DEPRESSION
loss of APPETITE PHOTOSENSITIVITY disorientation
MALABSORPTION thickened SKIN ENCEPHALOPATHY
NAUSEA HALLUCINATION
stomatitis irritability
VOMITING PARANOIA